Transcript RSI Drugs Powerpoint - Sites@Duke

Rapid Sequence
Intubation Drugs
Ryan J. Fink, MD
Raquel Bartz, MD
Duke University Medical Center
Dept. of Anesthesiology
Learning Objectives
• At the completion of this module the learner
should be able to:
– Choose the appropriate induction agent and
neuromuscular blocking agent for a given clinical
situation
– Calculate the appropriate dose of both induction
agent and paralytic for a given patient and clinical
situation
– Understand relative and absolute contraindications
for induction agents and paralytics
– Choose the appropriate vasopressor if blood
pressure decreases after induction/intubation
Administration of
General Anesthetics
for Rapid Sequence Intubation
Induction Agents: General Principles
• Choice of agent dependent on:
– Clinical status of the patient
– Clinicians familiarity with the agent
• Timing - Anesthetic agent should:
– Have time to take effect
– Be given before paralysis
Induction Agents: General Principles
• Primary concerns for agent choice:
– Hemodynamic stability and risk of hypotension
– Risk of additional respiratory depression
– ICP and cerebral perfusion
– History of ischemic heart disease
– Rapidity of effect
• Secondary concerns for agent choice:
– Amnestic properties
– Emetic properties
– Desired duration of effect
Induction Agents: General Principles
• Do no attempt intubation under suboptimal
conditions!
• Patient is ready for intubation when:
– Apneic
– Unresponsive (no lid reflex)
– Jaw is relaxed and mobile
Ideal Induction Agent
- Promote amnesia
- Hemodynamic stability
- Short-acting
- Minimal Side Effects
- Reversible
- Metabolized independent of liver or kidney
Potential Induction Agents
Etomidate
Propofol
Ketamine
Induction Drugs: Thiopental
• Intravenous sedative hypnotic
• Used in original description of RSI
• Rapid bolus doses = severe
hemodynamic instability
• NO LONGER A COMMON RSI AGENT
Induction Agents: Etomidate
• Intravenous anesthetic
• Short-acting
• Hemodynamic response:
– Minimal CV depression
• No major contraindications
– Relative CI: adrenal insufficiency
• No analgesic activity
Induction Agents: Etomidate
• Intubating Dose:
– 0.1 -0.2 mg/kg
– i.e. 70 kg pt = 7 - 14 mg
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•
•
•
Onset of Action: < 1 min (one arm-brain circulation)
T1/2: 10 – 20 min
Hypnosis (duration of action): 3 - 5 min
Side effects:
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–
–
–
Myoclonus; burning
Nausea/vomiting
Reduce dose in the elderly
Adrenal suppression (inhibition of 11-betahydroxylation  reduced cortisol and aldosterone)
Induction Drugs: Propofol
• Intravenous anesthetic
• Short-acting
• Hemodynamic response: ↓SVR, contractility, and
preload  often leading to ↓ BP
• No analgesic activity
• Contraindications: Hypotension, hypovolemia
Induction Drugs: Propofol
• Intubating Dose:
– 1 - 2 mg/kg
– i.e. 70 kg pt = 70 – 140mgmg
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•
•
Onset of Action: < 1 min (one arm-brain circulation)
Hypnosis (duration of action): 3 - 5 min
T1/2: 3 – 12 hours (due to release from fat stores)
Side effects:
– Burning at injection site
– Some anti-emetic effect
Induction Drugs: Ketamine
• Intravenous sedative  dissociative
anesthesia
• Structural analogue of phencyclidine
• Hemodynamic response: sympathetic
stimulation  ↑ HR, contractility, SVR  ↑
BP
• + analgesic activity
• Contraindications: Increased BP dangerous;
CAD
Induction Drugs: Ketamine
• Induction dose:
– 1 - 2 mg/kg
– 70 kg pt: 70 - 140 mg
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•
•
Onset of Action: < 1 min (one arm-brain circulation)
Hypnosis (duration of action): 11 -17 min
T1/2: 2 – 3 hours
Side effects:
–
–
–
–
↑ CBF, CMRO2, ICP
Nausea/vomiting
Excessive salivation
Hallucinations
Induction Agent Summary
Mechanism Intubating Onset Duration of
of Action
Dose
(min)
Hypnosis
(mg/kg)
(min)
Etomidate
Propofol
Ketamine
↑ GABA
↑ GABA
NMDA
antagonist
0.3
2 – 2.5
2
<1
<1
<1
3-5
3-5
11 - 17
Comments
- Adrenal suppression
- CV stability
- Nausea/vomiting
- Causes hypotension
- Burning at injection site
- Analgesia
- ↑HR, SVR, BP, ICP
- Preserves respiratory drive
- Broncho-dilator
Neuromuscular Blocking Agents
for Rapid Sequence Intubation
Neuromuscular Blocking Agents
• Advantages:
– ↓forceful regurgitation of gastric contents
– Relaxation oral-pharyngeal muscles
• Easy distraction of mandible and tongue
• Disadvantages:
– Apnea
– Oral-pharyngeal soft tissue collapse
• Available agents:
– Succinylcholine
– Rocuronium
Succinylcholine
• Depolarizing neuromuscular blocker
– Two ACh molecules together
– Binds to ACh receptor, opens channel
– Muscles fasciculation
• Major Advantage: rapid onset, brief duration
• Major Disadvantage: side effects
Succinylcholine
• Intubating dose: 0.6 – 1 mg/kg IV
– 70 kg pt: 42 - 70 mg
• Onset of action: 30 – 60 seconds
• T ½: 10 – 15 minutes
• Metabolism: Plasma cholinesterase
– 96% of pts have normal enzyme
– Prolonged duration w/ atypical gene
– Prolonged duration w/ conditions that ↓ PC
• Liver disease
• Pregnancy
Succinylcholine: Side Effects
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Bradycardia in adults after 2nd dose
↑ K+ (≈ 0.5 – 1.0 mEq/L)
↑ ICP
↑ Intraocular pressure
↑ Intra-gastric pressure
↑ Lower esophageal sphincter tone
↑ muscle tone in pts w/ myotonia congenita
or dystrophica
• Myalgias
Succinylcholine: Contraindications
• Hyperkalemia (approx 5.5 mEq/L or above)
• Increased risk of hyperkalemia:
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Burns or massive tissue trauma
Hemiparesis, spinal cord trauma
Approx 24 hours after acute injury
Neuromuscular disease, i.e. Guillain-Barre or ALS
Disuse atrophy, intra-abdominal abscess
• Malignant hyperthermia
• Some fractures (due to fasciculations)
Rocuronium
• Non-depolarizing neuromuscular blocker
– Amino-steroid molecule
– Competitive inhibition at ACh receptors
– No muscle fasciculations
• Major Advantage: rapid onset, lack of side effects
• Major Disadvantage: duration of action
Rocuronium
• Intubating Dose:
1.2 mg/kg
- 70 kg pt: 90 mg
• Onset of Action: 45 – 60 sec
• T1/2: 45 – 70 minutes
• Side effects: no significant SEs
• Contraindications
- Predicted difficult airway, difficult ventilation
- Liver disease can cause prolonged paralysis
- Bromide hypersensitivity
Neuromuscular Relaxant Summary
Intubating
Dose
(mg/kg)
Succinylcholine
Rocuronium
1 – 1.5
1 – 1.2
Onset
of
action
(sec)
30 - 60
45 - 60
Duration
of Action
(min)
10 - 15
45 - 70
Side effects
Contra-Indications
-Bradycardia
- ↑ K+
- ↑ intra- cranial,
gastric, & ocular
pressure
- Myalgias
-Hyperkalemia
- Denervating
disease
- Burns, massive
muscle injury
- Malignant
Hyperthermia
- none
-Difficult airway
- Liver disease
(relative CI)
Hemodynamics & Vasopressors
Drug
Systemic
Vascular
Resistance
Heart
Rate
Mean
Arterial
Pressure
Cardiac
Output
Etomidate
↔
↔
↔
↔
Propofol
↓↓
↓
↓↓
↓
Ketamine
↓/↑
↑↑
↑↑
↑
Adapted from Longnecker, 2008
Hemodynamics & Vasopressors
Drug
Systemic
Vascular
Resistance
Heart
Rate
Mean
Arterial
Pressure
Cardiac
Output
Etomidate
↔
↔
↔
↔
Propofol
↓↓
↓
↓↓
↓
Ketamine
↓/↑
↑↑
↑↑
↑
Adapted from Longnecker, 2008
Hemodynamics & Vasopressors
• ↓ SVR
= phenylephrine (50 – 100mcg boluses)
• ↓ HR
= atropine (0.5 mg bolus)
• ↓ Contractility = epinephrine (10 – 100 mcg boluses)
– Epinephrine if anaphylaxis suspected
• Continuous infusions may be necessary
RSI Drugs: Adjuncts
• Lidocaine
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IV local anesthetic
Esp. patients with traumatic brain injury/↑ ICP
↓ sympathetic response to laryngoscopy
Limited data/controversial
1.5 mg/kg IV, 2 minutes before RSI
Minimal side effects
Rapid Sequence Induction Drugs:
Summary
• Main drug classes for RSI
– General anesthetic
– Neuromuscular blocking agent
– Vasopressor
– Possibly lidocaine (for brain injury patients)
• Choice of drug depends on:
– Clinical situation and patient co-morbidities
– Clinical judgment